JP5559563B2 - Tire manufacturing method - Google Patents

Description

  The present invention relates to a tire manufacturing method for manufacturing a tire including a bead portion including a bead core and a bead filler and a carcass folded back to the bead core using a molding drum for molding a raw tire.

  In recent years, as environmental considerations have increased, there has been an increasing demand for reducing rolling resistance of pneumatic tires (hereinafter referred to as tires) in order to contribute to fuel saving of automobiles. In order to reduce the rolling resistance, it is important to reduce the weight of the tire.

  Thus, a tire is disclosed in which the height of the bead filler disposed on the outer side in the tire radial direction of the bead core is reduced (see, for example, Patent Document 1). According to this tire, by using a hard rubber material for the bead filler, the weight of the tire can be reduced without impairing riding comfort and tire durability.

  Such a tire is generally manufactured by the following method. That is, a carcass sheet constituting a carcass including a carcass cord (for example, a steel cord) is attached on a molding drum for molding a raw tire (so-called green tire). Next, a bead core and a bead filler are laminated in this order on the carcass sheet corresponding to the bead portion of the tire. Then, the width direction outer side part (part corresponding to a carcass folding | turning part) of a carcass sheet is turned back so that a bead core and a bead filler may be wrapped with a carcass sheet, and a green tire is shape | molded. The molded raw tire is vulcanized by a vulcanizer, whereby the above-described tire is completed (see, for example, Patent Document 2).

Japanese Unexamined Patent Publication No. 2007-45361 (2nd to 4th pages, FIGS. 1 and 2) Japanese Patent Laid-Open No. 11-348147 (pages 2 to 4 and FIGS. 2 to 4)

  However, the tire manufacturing method described above has the following problems. That is, the degree of freedom of deformation of the carcass seat is constrained due to the carcass cord being included in the carcass seat. Therefore, when manufacturing a tire having a low bead filler height, it is difficult to fold the carcass sheet along the shape of the bead filler, and there is a space between the folded outer portion of the carcass sheet in the width direction and the bead filler. Prone to occur. Accordingly, there is a problem that air is accumulated between the carcass and the bead core or bead filler, resulting in a tire manufacturing failure.

  Accordingly, the present invention provides a tire manufacturing method capable of reliably suppressing the occurrence of tire manufacturing defects due to air accumulation even when the height of the bead filler is set low in order to realize weight reduction of the tire. With the goal.

  In order to solve the above-described problems, the present invention has the following features. First, a first feature of the present invention is that a bead portion (bead portion 21) including a bead core (bead core 21A) and a bead filler (bead filler 21B) is formed using a forming drum (forming drum 100) for forming a raw tire. A tire manufacturing method for manufacturing a tire (pneumatic tire 1) including a carcass (carcass 12) folded back on the bead core, the carcass sheet (carcass sheet 12A) constituting the carcass on the molding drum And a step of laminating a sheet-like member (sheet-like member 30) at a predetermined position of the carcass sheet corresponding to the bead portion of the tire (sheet-like member laminating step) And laminating the bead core on the sheet-like member, and laminating the bead filler on the bead core. And a step of folding back the outer portion (outer portion 12e) in the width direction of the carcass sheet so as to wrap the bead core and the bead filler with the carcass sheet (carcass folding step). The sheet-like member is changed in shape when the raw tire is vulcanized, and is filled between the bead core and the bead filler and the carcass sheet in the folded carcass sheet. .

  According to such a feature, the tire manufacturing method includes a step of laminating a sheet-like member at a predetermined position of the carcass sheet corresponding to the bead portion of the tire. This sheet-like member changes its shape when the raw tire is vulcanized, and is filled between the bead core and the bead filler and the carcass sheet in the folded carcass sheet. Specifically, at the time of vulcanization of the green tire, the sheet-like member is pushed out from the highly rigid bead core side toward the bead filler. For this reason, the extruded sheet-like member is reliably filled in a space that tends to occur between the widthwise outer side portion of the folded carcass sheet and the bead filler. Therefore, air does not accumulate between the carcass and the bead part (bead core or bead filler), and the occurrence of tire manufacturing defects due to air accumulation can be reliably suppressed. This is particularly effective when the height of the bead filler is set to be low in order to reduce the weight of the tire.

  The second feature of the present invention relates to the first feature of the present invention, and is summarized in that the step of laminating the sheet-like member is performed before the carcass sheet is attached to the molding drum.

  A third feature of the present invention relates to the first or second feature of the present invention, and is summarized in that the sheet-like member is formed of the same material as the bead filler.

  According to a fourth aspect of the present invention, the height of the bead filler along the tire radial direction is H, and the width of the bead filler along the tire width direction is W. In this case, the gist of the bead filler is to satisfy the relationship of H / W ≧ 1.

  A fifth feature of the present invention relates to the first to fourth features of the present invention, and is summarized in that a height of the bead filler is less than 10 mm.

  According to the features of the present invention, a tire manufacturing method that can reliably suppress the occurrence of tire manufacturing defects due to air accumulation even when the height of the bead filler is set low in order to realize weight reduction of the tire. Can be provided.

FIG. 1 is a perspective view showing a part of a molding drum 100 according to the present embodiment. FIG. 2 is a front view (a view taken in the direction of arrow A in FIG. 1) showing a part of the molding drum 100 according to the present embodiment. FIG. 3 is a schematic diagram for explaining the tire manufacturing method according to the present embodiment. FIG. 4 is a cross-sectional view showing a part of the pneumatic tire 1 manufactured by the tire manufacturing method according to the present embodiment. FIG. 5 is a schematic diagram for explaining a tire manufacturing method according to a modified example.

  Next, an embodiment of a tire manufacturing method according to the present invention will be described with reference to the drawings. Specifically, (1) the configuration of the molding drum, (2) the tire manufacturing method, (3) the modified example, (4) comparative evaluation, (5) action / effect, and (6) other embodiments will be described.

  In the following description of the drawings, the same or similar parts are denoted by the same or similar reference numerals. However, it should be noted that the drawings are schematic and ratios of dimensions and the like are different from actual ones.

  Accordingly, specific dimensions and the like should be determined in consideration of the following description. Moreover, the part from which the relationship and ratio of a mutual dimension differ also in between drawings may be contained.

(1) Configuration of Molding Drum First, the configuration of the molding drum used in the tire manufacturing method according to the present embodiment will be briefly described with reference to the drawings. FIG. 1 is a perspective view showing a part of a molding drum 100 according to the present embodiment. FIG. 2 is a front view (a view taken in the direction of arrow A in FIG. 1) showing a part of the molding drum 100 according to the present embodiment.

  As shown in FIGS. 1 and 2, the molding drum 100 rotates about the shaft core 101. The molding drum 100 includes at least a main body outer peripheral portion 110 and a small-diameter outer peripheral portion 120.

  The main body outer peripheral part 110 is provided closer to the center C in the axial direction (direction S) of the molding drum 100 than the small-diameter outer peripheral part 120. The length of the main body outer peripheral portion 110 along the axial direction is longer than the length of the small-diameter outer peripheral portion 120 along the axial direction. A sheet-shaped first component member 10 such as an inner liner 11 or a carcass 12 is attached to the outer peripheral portion 110 of the main body.

  The small-diameter outer peripheral portion 120 is provided closer to the outer end in the axial direction of the molding drum 100 than the main body outer peripheral portion 110. The diameter of the small-diameter outer peripheral portion 120 is smaller than the diameter of the main body outer peripheral portion 110. A part of the first component member 10 described above is attached to the small-diameter outer peripheral portion 120. The second component member 20 such as the bead portion 21 including the bead core 21 </ b> A and the bead filler 21 </ b> B is attached to the small-diameter outer peripheral portion 120. In addition, the sheet-like member 30 mentioned later is provided between the 1st structural member 10 and the 2nd structural member 20 (refer FIG. 2).

  In such a molding drum 100, the outer portion 12e (the portion corresponding to the carcass folded portion) in the width direction of the carcass sheet 12A constituting the carcass 12 is folded back toward the axial center C of the molding drum 100, and the raw tire (Shown). Note that the configuration and method of folding the outer portion 12e of the carcass sheet 12A in the molding drum 100 is a general configuration (for example, Japanese Patent Application Laid-Open No. 2000-225654), and thus the description thereof is omitted here.

(2) Tire manufacturing method Next, the structure of the tire manufacturing method which concerns on this embodiment is demonstrated, referring FIGS. FIG. 3 is a schematic diagram for explaining the tire manufacturing method according to the present embodiment. FIG. 4 is a cross-sectional view showing a part of the pneumatic tire 1 manufactured by the tire manufacturing method according to the present embodiment.

  In the tire manufacturing method, a green tire (pneumatic tire 1 (see FIG. 4)) is manufactured using the molding drum 100 described above. As shown in FIGS. 2 and 3, the tire manufacturing method includes at least a first component member attaching step, a sheet-like member lamination step, a second component member lamination step, and a carcass folding step.

  First, as shown to Fig.3 (a), the 1st structural member 10 is affixed on a shaping | molding drum at a 1st structural member sticking process. Specifically, a liner sheet (not shown) constituting the inner liner 11 and a carcass sheet 12A are attached in this order to a part of the main body outer peripheral part 110 and the small diameter outer peripheral part 120.

  Next, as shown in FIG. 3 (b), in the sheet-like member lamination step, the shape changes to a predetermined position of the carcass sheet 12A corresponding to the bead portion 21 of the pneumatic tire 1 during vulcanization of the raw tire. The sheet-like members 30 to be stacked are stacked.

  Here, the sheet-like member 30 is formed of the same material as the bead filler 21B. For example, the thickness of the sheet-like member 30 is 0.8 mm, and the width of the sheet-like member 30 is 50 mm.

  The sheet-like member 30 is filled between the bead core 21A and the bead filler 21B and the carcass sheet 12A (the carcass 12 and the outer portion 12e) in the folded carcass sheet 12A when the raw tire is vulcanized. For this reason, the sheet-like member 30 needs to have a thickness and a width that are at least filled.

  Next, as shown in FIG. 3C, in the second component member stacking step, the bead core 21A is stacked on the sheet-like member 30, and the bead filler 21B is stacked on the bead core 21A. That is, the sheet-like member 30, the bead core 21A, and the bead filler 21B are laminated in this order.

  Here, as shown in FIG. 4, when the height of the bead filler 21B in the tire radial direction is H and the width along the tread width direction of the bead filler is W, the bead filler 21B is H / W ≧ Satisfies 1 relationship. In the present embodiment, the height H of the bead filler 21B is less than 10 mm.

  Next, as shown in FIG. 3D, in the carcass folding step, the outer portion 12e of the carcass sheet 12A is set to the axial center C of the molding drum 100 so as to wrap the bead core 21A and the bead filler 21B with the carcass sheet 12A. Turn it back and mold the raw tire.

  Thereafter, the molded raw tire is vulcanized by a vulcanizer (not shown). As a result, as shown in FIG. 4, the pneumatic tire 1 in which the sheet-like member 30 is filled (embedded) between the bead core 21 </ b> A and the bead filler 21 </ b> B and the carcass 12 is completed.

(3) Modification Example Next, a modification example of the tire manufacturing method according to the above-described embodiment will be described with reference to the drawings. FIG. 5 is a schematic diagram for explaining a tire manufacturing method according to a modified example. In addition, the same code | symbol is attached | subjected to the same part as the tire manufacturing method which concerns on embodiment mentioned above, and a different part is mainly demonstrated.

  In embodiment mentioned above, a sheet-like member lamination process is performed after a 1st component member sticking process. On the other hand, in the modified example, the sheet-like member lamination step is performed before the first component member attaching step.

  Specifically, as shown in FIG. 5A, in the sheet-like member laminating step, a sheet-like shape is formed at a predetermined position of the first component member 10 (carcass sheet 12A) corresponding to the bead portion 21 of the pneumatic tire 1. The members 30 are stacked.

  Next, as shown in FIG. 5 (b), in the first component member affixing step, the first component member 10 (carcass sheet 12 </ b> A) on which the sheet-like member 30 is previously laminated is affixed on the molding drum 100. In addition, about a 2nd structural member lamination | stacking process and a carcass folding | turning process, it is the same as that of embodiment mentioned above.

(3) Comparative Evaluation Next, in order to further clarify the effect of the present invention, comparative evaluation performed using the tire manufacturing methods according to the following comparative examples and examples will be described with reference to Table 1. In addition, this invention is not limited at all by these examples.

  In the tire manufacturing method according to the comparative example, a plurality of pneumatic tires (155 / 65R14) were manufactured without performing the above-described sheet-like member lamination step. On the other hand, in the tire manufacturing method according to the example, the sheet-like member lamination step was performed, and a plurality of pneumatic tires (155 / 65R14) similar to those of the comparative example were manufactured.

  As a result, as shown in Table 1, the carcass 12 and the bead portion 21 (bead core 21A) that are folded back by performing the sheet-like member laminating step, that is, by laminating the sheet-like member 30 at a predetermined position of the carcass sheet 12A. In addition, it was found that air does not accumulate between the filler and the bead filler 21B), and that no defective manufacturing of the pneumatic tire occurs.

(4) Action / Effect In the embodiment described above, the tire manufacturing method includes a sheet-like member laminating step of laminating the sheet-like member 30 at a predetermined position of the carcass sheet 12A corresponding to the bead portion 21 of the pneumatic tire 1. Is included. The sheet-like member 30 changes its shape when the raw tire is vulcanized, and is filled between the bead core 21A and the bead filler 21B and the carcass sheet 12A in the folded carcass sheet 12A. Specifically, at the time of vulcanization of the raw tire, the sheet-like member 30 is pushed out from the highly rigid bead core 21A side toward the bead filler 21B. For this reason, the extruded sheet-like member 30 is reliably filled in a space that is likely to occur between the outer portion 12e of the folded carcass sheet 12A and the bead filler 21B. Therefore, air does not accumulate between the carcass 12 and the bead part 21 (the bead core 21A or the bead filler 21B), and the production failure of the pneumatic tire 1 due to the air accumulation can be reliably suppressed. In particular, this is effective when the height of the bead filler 21B is set low in order to reduce the weight of the pneumatic tire 1.

  Further, the sheet-like member lamination step is performed before the second component member lamination step. If the sheet-like member laminating step is performed after the second component member laminating step, when laminating the sheet-like member 30 on the bead core 21A and the bead filler 21B, the bead portion 21 and the sheet are pre-vulcanized. Air accumulates between the cylindrical member 30.

  In the embodiment, the sheet-like member 30 is formed of the same material as the bead filler 21B. This makes it easier for the sheet-like member 30 to become familiar with the bead filler 21B during vulcanization of the raw tire. For this reason, compared with the case where the sheet-like member 30 is formed by a member different from the bead filler 21B, it becomes difficult to peel between the sheet-like member 30 and the bead filler 21B. Therefore, durability of bead part 21 improves and durability of pneumatic tire 1 itself also improves.

  In the embodiment, the bead filler 21B satisfies the relationship of H / W ≧ 1. Moreover, the height H of the bead filler 21B is less than 10 mm. This is effective when the height of the bead filler 21 </ b> B is set low in order to reduce the weight of the pneumatic tire 1.

  In the embodiment (modified example), the sheet-like member stacking step is performed before the first component member attaching step. That is, before supplying the carcass sheet 12A to the molding drum 100, the sheet-like member 30 can be laminated at a predetermined position of the carcass sheet 12A. According to this, it becomes unnecessary to laminate | stack the sheet-like member 30 on the carcass sheet | seat 12A on the shaping | molding drum 100, and generation | occurrence | production of the manufacturing defect of a pneumatic tire can be suppressed with the work man-hour equivalent to the past.

(5) Other Embodiments As described above, the contents of the present invention have been disclosed through the embodiments of the present invention. However, it is understood that the description and drawings constituting a part of this disclosure limit the present invention. Should not. From this disclosure, various alternative embodiments, examples, and operational techniques will be apparent to those skilled in the art.

  For example, the embodiment of the present invention can be modified as follows. Specifically, in the tire manufacturing method, it has been described that the molding drum 100 described in the embodiment is used. However, the present invention is not limited to this, and a molding drum having a configuration different from that of the embodiment may be used. Of course.

  In the embodiment, the tire manufacturing method has been described as using the bead filler 21B that satisfies the relationship of H / W ≧ 1, but the present invention is not limited to this, for example, the bead that satisfies the relationship of H / W <1. The filler 21B may be used. In addition, the height of the bead filler 21B may be 10 mm or more, and the sheet-like member 30 may be a material different from the bead filler 21B.

  As described above, the present invention naturally includes various embodiments that are not described herein. Therefore, the technical scope of the present invention is determined only by the invention specifying matters according to the scope of claims reasonable from the above description.

  DESCRIPTION OF SYMBOLS 1 ... Tire, 10 ... 1st structural member, 11 ... Inner liner, 12 ... Carcass, 12e ... Outer part, 12A ... Carcass sheet, 20 ... 2nd structural member, 21 ... Bead part, 21A ... Bead core, 21B ... Bead filler , 30 ... sheet-like member, 100 ... molding drum, 101 ... shaft core, 110 ... outer periphery of main body, 120 ... outer periphery of small diameter

Claims (4)

A tire manufacturing method for manufacturing a tire having a bead portion including a bead core and a bead filler and a carcass folded back on the bead core using a molding drum for molding a raw tire,
A step of attaching a carcass sheet constituting the carcass on the molding drum;
Laminating a sheet-like member at a predetermined position of the carcass sheet corresponding to the bead portion of the tire;
Laminating the bead core on the sheet-like member, and laminating the bead filler on the bead core;
Folding back the widthwise outer side portion of the carcass sheet so as to wrap the bead core and the bead filler with the carcass sheet,
The sheet-like member is changed in shape at the time of vulcanization of the raw tire, and is filled between the bead core and the bead filler and the carcass sheet in a folded carcass sheet ,
The said sheet-like member is a tire manufacturing method formed with the same material as the said bead filler .   The tire manufacturing method according to claim 1, wherein the step of laminating the sheet-like members is performed before the carcass sheet is attached to the molding drum. The height along the tire radial direction of the bead filler and H, if the width along the tire width direction of the bead filler and is W, the bead filler according to claim 1 satisfying the relation of H / W ≧ 1 Or the tire manufacturing method of 2. The tire manufacturing method according to any one of claims 1 to 3 , wherein a height of the bead filler is less than 10 mm.

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